摘要
采用SMPS-CCNC联用的方法,于2018年7月~8月在南京北郊地区,对大气环境中气溶胶的云凝结核(CCN)活化特性进行了观测研究.观测结果表明南京北郊地区夏季的气溶胶吸湿性参数(κ)平均值为0.31;不同过饱和度(S)下的CCN数浓度(NCCN)为(1.43±0.60)×10^(3)个/cm^(3)(S=0.13%),(2.64±1.06)×10^(3)个/cm^(3)(S=0.23%),(3.88±1.35)×10^(3)个/cm^(3)(S=0.41%),(4.81±1.64)×10^(3)个/cm^(3)(S=0.59%),(5.58±1.88)×10^(3)个/cm^(3)(S=0.77%),并且有明显日变化特征,峰值出现在傍晚18:00~23:00时之间;夏季新粒子生成使总气溶胶数浓度(NCN)和NCCN显著提升;同时对比分析典型天气日发现,不同S下双高污染日(高PM_(2.5)浓度、高O3浓度)的NCCN高于对照日(低PM_(2.5)浓度、低O3浓度)的NCCN,κ值(0.33)也大大高于对照日的κ值(0.22),其主要原因是受PM_(2.5)的化学成分特征的影响,且夏季较高的O3浓度加快了光化学或臭氧氧化反应,促进了二次气溶胶的形成和老化.
The activation characteristics of cloud condensation nuclei(CCN)of atmospheric aerosols were observed over the northern suburbs of Nanjing from July to August 2018 using the SMPS-CCNC coupling method.The results showed that an average value of the aerosol hygroscopicity parameter(κ)in summer was 0.31 there;the CCN number concentrations(NCCN)at different supersaturations(S)were(1.43±0.60)×10^(3)cm^(-3)(S=0.13%),(2.64±1.06)×10^(3)cm^(-3)(S=0.23%),(3.88±1.35)×10^(3)cm^(-3)(S=0.41%),(4.81±1.64)×10^(3)cm^(-3)(S=0.59%),and(5.58±1.88)×10^(3)cm^(-3)(S=0.77%),respectively.The peak values were found between 18 and 23 LT.The NCCN of the double high pollution day(high PM2.5 concentration and high O3 concentration)was higher than that of the control day(low PM2.5 concentration and low O3 concentration)under different S;and theκvalue(0.33)was also much higher than that of the control day(0.22).These could be mainly attributed to the chemical composition of PM2.5 and the higher O3 concentration in summer.The higher O3 concentration in summer would accelerate the photochemical or ozone oxidation reaction and therefore promote the formation and aging of secondary aerosols.
作者
周莉
马嫣
郑军
邹华
ZHOU Li;MA Yan;ZHENG Jun;ZOU Hua(Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control,School of Environmental Science and Engineering,Nanjing University of Information Science&Technology,Nanjing 210044,China)
出处
《中国环境科学》
EI
CAS
CSCD
北大核心
2023年第5期2210-2219,共10页
China Environmental Science
基金
国家自然科学基金资助项目(41975172,42275116)。
关键词
云凝结核
活化特性
吸湿性参数
cloud condensation nodules
activation properties
hygroscopicity parameters
